It is well known to treat yarns and/or fabrics with chemical compositions to improve flame resistance. By way of example, in one known process, ammonia and tetrakis hydroxymethyl phosphate salts are used. However, such chemical treatments may render undesired odors and/or degrade the physical strength of the fabric.
It is also known to use inherently flame resistant fibers such as aramid fiber and the like. While such fibers may provide good flame resistance, they may also be difficult to dye and provide lower levels of physical comfort for the user.
Flame resistant cellulosic fibers are also known. However, such fibers are typically characterized by relatively low mechanical strength levels so as to have a disadvantage for long term use. Moreover, the high absorption capacity of the fibers results in retaining moisture when the user perspires.
Halogen containing fibers such as modacrylics and PVC are known to provide good flame resistance, but they tend to have relatively poor heat resistance and do not form a stable char for user protection.
Flame resistant fabrics with blends containing modacrylics in combination with cellulosic or synthetic fibers are also known. Relatively large amounts of metal oxides may be added to the modacrylic fibers to promote flame resistance. Exemplary references include U.S. Pat. Nos. 5,503,915; 5,503,916; 5,506,042; and U.S. application 20050148256 all of which are incorporated by reference in their entirety.
Flame resistant fabrics with yarns containing blends of modacrylic fiber and polysilic acid embedded rayon (such as VISIL®) is known for use in bedding. However, fabric physical strength is such that the production of apparel may be problematic due to degradation caused by abrasion and frequent washing.
Finally, it is known to use high loft non-woven fabrics containing blends of modacrylic fiber, polysilic acid embedded rayon, low melting point polyester and PET as a flame barrier in mattresses. However, forming fabrics from these same blends does not provide sufficient flame resistance for apparel use.